1. Field of the Invention
The present invention relates to a lifter apparatus for a vehicle seat which moves a seat cushion up and down.
2. Description of Relevant Art
A seat of a vehicle is provided with a lifter apparatus which moves a seat cushion up and down to adjust a viewpoint height of a sitting person or feeling of sitting. In this kind of the lifter apparatus, a shaft to be rotated is provided between a pair of movable rails which are fixed to both sides of a seat cushion and a lever which is mounted to an end portion of the shaft. The shaft is fixed with a pair of bracket pieces to rotate the shaft in itself. These bracket pieces each are formed with a supporting opening of the same size, and a nut in a cylindrical shape is previously mounted in the supporting openings with the nut passing through supporting openings. The nut is screwed by a lead screw which projects from a motor fixed on a side of the movable rail. When the lead screw is rotated, the bracket pieces swing forward and backward, the shaft is rotated in a direction where the bracket pieces swing. A spacer is mounted to a tip end of the lead screw which passes through the nut, the spacer to prevent the nut from coming off.